Mespilia
Desor, in Agassiz & Desor, 1846, p. 357

Apical disc dicyclic, with gonopores close to the outer margin; inner region of genital plates tuberculate, forming a semi-regular ring around the periproct. Perirproct subcircular; periproct plates small and undifferentiated.

Ambulacral plating trigeminate. Pore-pairs arranged with the middle pore-pair (on the occluded plate) adradial to the other two; forming a single adradial band. Not expanded adorally and no pore-crowding close to the peristome.

Two subequal tubercles on each ambulacral plate.

Wide perradial and interradial naked zones developed from apex to well beneath the ambitus.

Small angular pits at sutural triple points on perradius and interradius; horizontal sutures without pits.

Interambulacral plates with tuberculation confined to adradial margin from ambitus aborally. Central primary tubercle small and flanked by subequal tubercles latterally and above.